Approach

Start at the South Lake trailhead (9,820') for Bishop Pass and head south. Initially this trail will lose elevation, something you'll definately remember on the hike out ;-) In 0.8 miles from the trailhead, you'll run into junction with the trail to Treasure Lakes. Follow the trail to Treasure Lakes, however, at 10,400' (or lower) you'll want to get off trail to the right and hike up some slabs and scree over the lower part of Mount Gilbert's NW Ridge. This will get you into Gilbert basin from where Gilbert's North Couloir is reachable. Continue west Thompsons Northeast Face to climb any of it's couloirs or the North Ridge (aka Thompson Ridge).

Doing the approach on the first day and camping below the couloirs is a popular option though it's possible to do this in one day from South Lake if you are fast. This probably requires downclimbing or rappelling the couloir.

Route Description

Of the three couloirs on the Northeast Face, the Harrington Couloir is the right-most one, very obvious, wide and straight. Just go straight up. There are some rock belays possible on the west side (climber's right). Secor lists the length of this couloir at 900' reaching 70° at the top. Bob Pickering measured the couloir at 600' with an angle of "38-54 degrees sustained with one bulge at 60 degrees." For the vertical, it depends on where you start measuring which can account for the discrepancy.

Descent

The descent has become the crux for some trips because there are no easy walk-offs, at least short ones. Here are several options:

Downclimb: One popular descent for any of Thompson's ice couloirs is to downclimb the Harrington Couloir.

Rappel: It's possible to rappel using a combination of V-threads, ice bolards, and rock anchors if you don't mind leaving some gear.

Thompson Ridge: If you don't want to do either of the above, you can descend the class 3 Thompson Ridge, however, this route may be a bit longer than desired and coming off the ridge earlier than the class 3 route means rappeling technical terrain.

Essential Gear

Two ice tools, crampons, and a helmet. If you want to rope up, a few ice screws and nuts are useful. As of October 2002, there was a nut and old pin up on the right side.

Miscellaneous Info

If you have information about this route that doesn't pertain to any of the other sections, please add it here.

We rapped the couloir on September 25th, 2005 and here's what we found (directions described based on looking DOWN the couloir):

Rappel 1: There is a broad flat-faced boulder/rock to the right with a ledge system on it. If you stand on the ledge you can reach rapp slings for the second rappel.

Rappel 2: Angle left toward the opposite side of the couloir. Here there are some more rapp slings and some sloping loose ledges holding snow. As an alternative, there is an old cam left in a crack beneath these ledges where a nicer snow platform can be ade.

Rappel 3: Stay to the left side of the couloir, and another set of rapp slings can be found alongside the moat - we had to chop steps here to fit everyone (5 people!)

Rappel 4: Keep to the left and you will come across one more rapp anchor. It is hard to see until you are below it. There was a large bridged moat between us and the wall with anchors. The anchor is composed of one nut in a vertical crack, one chock-pebble girth-hitched in the same crack, and our added sling across a large detached flake beneath the crack. This rappel conveniently gets you to the bergschrund.

We needed the full 200ft rope length to reach these anchors. If you're climbing with one 60m rope, it will not reach unless you are using a retrieval line!